#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include <assert.h>
#include <string.h>

char* my_strcat(char* dest, const char* src)
{
	assert(dest && src);
	char* ret = dest;

	while (*dest != '\0')
	{
		dest++;
	}
	while (*src != '\0')
	{
		*dest++ = *src++;	
	}
	*dest = '\0';

	return ret;
}
int main()
{
	char arr1[20] = "hello ";
	char arr2[] = "world";

	my_strcat(arr1, arr2);

	printf("%s\n", arr1);
	return 0;
}